Enhancement of an operational Energy Management System (EMS) using the latest client-server and workstation technology while protecting the original investment

Traditionally, Energy Management Systems (EMS) used by power utilities were based on a ´closed´ system architecture. For such systems, all application software is restricted to run on a proprietary platform. The utilities have to rely heavily on the EMS vendor for the software and hardware support. Application software development requires excessive effort because off-the-shelf software is not available. Data sharing with other computer systems is extremely difficult. System upgrading is difficult because it often requires a system replacement, which causes interruptions to the power system operation. The trend of ´open´ system architecture has a great impact in the EMS industry. Almost all the new EMS systems are now based on the open system architecture. Utilities no longer need to rely on a single vendor to supply all the software and hardware for the EMS. They can choose a variety of computer hardware and then purchase application software from different vendors. Information sharing is easier. System upgrades can be done incrementally by upgrading only the individual subsystem that has to be enhanced. For the existing users of closed EMS systems, it may not be justifiable to replace the EMS immediately with one based on open system architecture. This paper describes how China Light & Power Co. Ltd. (CLP) enhanced the EMS so that the benefits of open systems can be recognised without replacing the EMS